In his keynote address at a security conference today, Apple co-founder Steve Wozniak admitted he has enjoyed many adventures in hacking often for the sake of pranks on friends and family, especially back in his college days and the early years of working on computers and the internet.

“I like to play jokes,” said the Wozniak jovially, as he addressed his audience of thousands of security professionals attending the ASIS Conference in Chicago. The famed inventor at Apple admitted he also had some fun with light-hearted forays into hacking computer and telecommunications networks several decades ago back in his college years and while learning about electronics and computers.

People with imagination in engineering are naturally drawn to the idea of finding ways to bypass security controls as part of the process of discovering how things work, and Wozniak said this was especially true of himself.

“But I never once hacked a computer for real,” he told his audience, meaning his break-ins and intrusions were done in the spirit of exploration, never for profit or malice. One youthful prank involved some experimentation into a shared computer system several where he left nine pages of Polish jokes that were dumped on users.

As a young man in college when he read an article about how tone signalling techniques could be used to manipulate telephone networks to set up calls, he said he became intrigued and had to find out more and even try it himself. He went out and learned more about the exact frequencies and tried them out on the telephone system. “I wanted to explore the network,” he said. It was all a form of ‘White Hat hacking’ he says he did, but never for purposes of stealing or avoiding paying bills.

As to his famous partnership with Steve Jobs, Wozniak said the two “became best friends instantly” and they shared a fascination with finding out how networks worked in sometimes unorthodox ways.

Circumventing the controls placed by authority was sometimes part and parcel of satisfying the enormous drive he had as a budding computer engineer to experiment and grow in knowledge, he points out. Wozniak said he had a friend with the key to the college computing room and he snuck in in the middle of the night to run his computing programs on punch cards. He admitted he also used to sneak into at least one eminent Stanford institution’s lab every Sunday when it was supposed to be closed to find electronics and science manuals so he could learn more. It all just shows you “the brightest people in the world tend of leave their doors unlocked,” Wozniak said.

Wozniak said many of his break-in stunts were often combined with a prank, such as when he guessed his stepson’s password for the Macintosh and made the files he found hard to access, while also scheming with his wife to leave a folder marked ‘from Mom’. “He was livid,” said Wozniak about the prank.

Wozniak said one of his favourite pranks was coming up with a TV jammer that he secretly used to convince friends their TV sets were malfunctioning, while at the same time instructing them in outlandish ways to ‘fix’ the problems – until he secretly stopped jamming their sets.

All of this youthful exuberance at the time may have occurred “because I was a geek, and had little hope of finding a girlfriend or a wife,” Wozniak says.